A thermal image can be obtained by sensing infrared (IR) radiation, such as with an array of bolometers or microbolometers, or with some other thermal detecting focal-plane array (FPA) structure or thermal imager. A bolometer detects particular bands of electromagnetic radiation (such as IR) by exposing a thermally isolated material that absorbs these bands to a source of the radiation and measuring the temperature increase in the absorbing material. For example, a resistive thermometer can be connected to two ends of the material, and current can be driven through the material to measure the resistance, which changes with the temperature of the material. An array of such bolometers can produce an image from these measured bands of radiation. An FPA is an array of detectors on which incoming radiation is focused, together with circuitry, such as a readout integrated circuit (ROIC), to drive the array and process the sensor readings.